This invention relates to polymerization of ethylenically unsaturated monomers, preferably methyl methacrylate. More particularly, it relates to an initiator-activator system and process for such polymerization.
Aqueous activator systems with bisulfites in solution along with initiators of metal salts of hemi-peresters of maleic acid are disclosed in U.S. Pat. Nos. 4,184,030; 4,188,315; 4,189,451 and 4,197,215 (1980) all to Dudyniak. U.S. Pat. No. 3,154,600--Munn (1964) discloses a syrup and curing system. These patents are incorporated herein by reference.
The solution activator systems of those patents work well, but for high speed industrial processes, such as for sheet casting and injection molding of forms, it would be better to have a faster acting polymerization and cure system that can be mixed efficiently with syrup at high speed.